var express = require("express");
var fetch = require("node-fetch");
var qs = require("qs");
var serveFavicon = require("serve-favicon");
var gm = require("gm");
var fs = require("fs");

var app = express();
app.set("trust proxy", "127.0.0.1");
app.listen(process.env.PORT || 39, process.env.ADDRESS);
app.use(serveFavicon("ミク.png"));
app.use((req,res,next)=>{req.rawQuery = req.url.includes('?') && req.url.substr(req.url.indexOf('?')+1);next();});

var list = require("./list.json");
var list_r18_indices = [], list_safe_indices = [];
for (let i = 0, h = list.length; i < h; i++) if (list[i][2]) list_r18_indices.push(i); else list_safe_indices.push(i);
var ipa_lastload_map = {};


function getRandomId(allow_r18) {
	if (allow_r18?.toLowerCase() == "only") {
		return list[list_r18_indices[Math.floor(Math.random() * list_r18_indices.length)]][0];
	} else if (allow_r18 != null) {
		return list[Math.floor(Math.random() * list.length)][0];
	} else {
		return list[list_safe_indices[Math.floor(Math.random() * list_safe_indices.length)]][0];
	}
};


function getRandomUrl(req) {
	var s = req?.params.settings ? `/${req?.params.settings}` : '';
	var d = getRandomId(req?.query.allow_r18);
	return `${s}/https://www.pixiv.net/en/artworks/${d}`;
}


async function serveId(id, req, res, next) {
	try {
		console.log(new Date().toLocaleString(), req.ip, req.url);
		
		let pages = list.find(x => x[0] == id)?.[1];
		if (!pages) {
			let data = await (await fetch(`https://pixiv.net/ajax/illust/${id}/pages`, {
				headers: { "Host": "www.pixiv.net" }
			})).json();
			if (data.error) {
				res.status(502).type("text").send(data.message);
				return;
			}
			pages = data.body;
		}

		var size = req.query.size || "original";
		var url = pages[0].urls[size];
		if (!url) return res.status(400).type("text").send(`size must be one of the following: ${Object.keys(pages[0].urls).join(', ')}`);
		
		var pxreq = await fetch(url, { headers: {"Referer": "https://www.pixiv.net"} });
		//if (pxreq.status != 200 && size == "original") {
		//	res.header("X-Using-Backup", '1');
		//	pxreq = await fetch(`https://39.hmbp.gq/https://www.pixiv.net/en/artworks/${id}?noredirect`);
		//}

		res.status(pxreq.status);
		res.type(pxreq.headers.get("Content-Type"));
		res.header("Content-Disposition", `filename=${url.split('/').pop()}`);
		res.header("X-Pixiv-Id", id);
		if (req.query.auto) res.header("Refresh", `${Number(req.query.auto)}; url=${getRandomUrl(req)}`);
		if (req.query.drawsource != null && pxreq.headers.get("Content-Type").startsWith("image")) {
			gm(pxreq.body).drawText(2, 12, size == "thumb_mini" ? id : `https://www.pixiv.net/en/artworks/${id}`).stream().pipe(res);
		}
		else pxreq.body.pipe(res);

		fs.appendFileSync(`logs/${req.ip.replace(/[:\/]/g, '-')}.csv`, `${new Date().toISOString()},${id}\n`);

	} catch(error) {
		next(error);
	}
}

// original HTML-less site for humans via web browser.
// - click refresh to get different image
// - delete left half of url to get to source
// - hacked querystring so it's before source url
app.get("(/:settings)?/https://www.pixiv.net/en/artworks/:id", function (req, res, next) {
	if (req.rawQuery) {
		let settings = req.params.settings || '';
		if (settings) settings += "&";
		settings += req.rawQuery;
		return res.redirect(`/${settings}/https://www.pixiv.net/en/artworks/${req.params.id}`);
	}
	
	if (req.params.settings) req.query = qs.parse(req.params.settings);
	
	if (ipa_lastload_map[req.ip] == req.url) return res.redirect(getRandomUrl(req)); 
	else ipa_lastload_map[req.ip] = req.url;

	serveId(req.params.id, req, res, next);
});

// initial randir
app.get('/', (req, res) => {
	res.redirect((req.rawQuery ? `/${req.rawQuery}` : '') + getRandomUrl(req));
});

// direct random image without redirects
app.get("/img/random", (req, res, next) => {
	serveId(getRandomId(req.query.allow_r18), req, res, next);
});

// simple serve id without redirects
app.get("/img/:id", (req, res, next) => {
	res.header("Cache-Control", "max-age=99999999999999");
	serveId(req.params.id, req, res, next);
});

// plaintext random id(s) for scripts
app.get("/randomid", function (req, res) {
	var count = Number(req.query.count) || 1;
	count = Math.min(count, 100);
	var ids = [];
	for (let i = 0; i < count; i++) ids.push(getRandomId(req.query.allow_r18));
	ids = ids.join(',');
	res.type("text/plain").send(ids);
});


// log site
app.get("/log", function (req, res) {
	res.redirect(`/log/${req.ip}`);
});
var log_html = fs.readFileSync("log.html", "utf8");
app.get("/log/:ipa", function (req, res) {
	res.send(log_html);
});
app.get("/log/:ipa/csv", function (req, res) {
	res.sendFile(req.params.ipa.replace(/[:\/]/g, '-') + '.csv', {root: process.cwd() + "/logs/"});
});